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Discussion Starter · #1 ·
This is driving me crazy!. My 05 S60R has been periodically over boosting. If I unplug the TCV it will never go over 7 psi (wastegate pressure) so this tells me the ECU is sending a bad signal, or the TCV is broken some how. Well I have now replaced the TCV and the boost pressure sensor for good measure. Still it will overboost completely unrestricted. Im at a lose, there is one check engine light that comes on and its P0076, (ECM-612D Intake camshaft reset valve -- Signal too low). I cleaned both the CVVT's and reset the ECU and it ran great for a couple days, but then it started overboosting again and the check engine light came back on. I dont know if the code is related to the boost problem but like I said this is driving me crazy. If any one has any idea of what to try I would really appreciate it.

Thanks guys
 

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Is the caR tuned?
 

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Are you using a stock TCV (made by Pierburg)? If not, and you're using an aftermarket "HD-TCV" that is based on a valve made by MAC (such as ARD, SNABB, Phuzzy Motorsports, etc.), then that may be your problem, because the MAC valves that they are using are not designed for automotive applications and will fail to correctly control boost when exposed to typical underhood temperatures/conditions.
 

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Discussion Starter · #4 ·
As far as I know the car is not tuned, however when it runs correctly it seems to have peak boost of 18 PSI. I did try a phuzzy motorsports MAC valve replacement but reinstalled the original Pierburg one since it did not fix the issue.
 

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As far as I know the car is not tuned, however when it runs correctly it seems to have peak boost of 18 PSI. I did try a phuzzy motorsports MAC valve replacement but reinstalled the original Pierburg one since it did not fix the issue.
FWIW, stock R's peak at 14.7psi or roughly 1 bar, so it seems that yours has a tune on it.
 

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Discussion Starter · #6 ·
Yeah its always been odd to my why it peaks at a higher boost, is it possible that the tune went bad? At this point the only thing that makes sense it a bad ECU. Is there anyway to test for that?
 

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Assuming you don't have a tune you don't know about, it could be the boost sensor is going bad. Garbage in, garbage out since that is the sensor that is used to control boost.
 

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Discussion Starter · #8 ·
Well I replaced the boost sensor and still no change. I know the waste gate is good, I know the TVC is good, I know the boost sensor is good. Whats left in the system that could cause this?
 

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Well I replaced the boost sensor and still no change. I know the waste gate is good, I know the TVC is good, I know the boost sensor is good. Whats left in the system that could cause this?
Have you tried another stock Pierburg unit? Assuming the original one you had was bad and the car didn't like the MAC valve.. just a thought.
 
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